Jérôme Lejeune facts for kids

Jérôme Jean Louis Marie Lejeune (born 13 June 1926 – died 3 April 1994) was a French doctor who specialized in children's health (a pediatrician) and studied genes (a geneticist). He is best known for discovering that certain health conditions are caused by problems with chromosomes. His most famous discovery was linking Down syndrome to an extra copy of chromosome 21, also known as trisomy-21. He also identified the cause of cri du chat syndrome.

Dr. Lejeune was a strong supporter of human life. He believed that certain medical tests, like amniocentesis (a test during pregnancy), should not be used to choose which babies are born based on their genes. He is honored in the Catholic Church and was declared "Venerable" by Pope Francis on 21 January 2021. This is a step towards becoming a saint.

His Work and Discoveries

Discovering Trisomy 21

In 1958, Jérôme Lejeune made a very important discovery. He was working in a lab with Raymond Turpin and Marthe Gautier. He found that Down syndrome is caused by having an extra copy of chromosome 21. Chromosomes are like tiny packages in our cells that contain all our genetic information. Humans usually have 46 chromosomes, but people with Down syndrome have 47, with an extra chromosome 21.

Lejeune wrote in his lab notebooks that he made this observation on 22 May 1958. The discovery was officially announced by the French Academy of Sciences. Lejeune was listed as the main author, Gautier as the second, and Turpin as the senior author. This was the first time anyone showed that a problem with learning or development was linked to a specific chromosome problem.

How the Discovery Happened

In the early 1950s, Lejeune joined Raymond Turpin's department. Turpin suggested Lejeune study the causes of Down syndrome. By 1953, Lejeune and Turpin found a link between a person's traits and their fingerprints (called dermatoglyphs). They noticed that children with Down syndrome had unusual patterns on their hands. This suggested that something happened very early in their development, when the embryo was forming.

In 1956, scientists in Sweden found that humans have exactly 46 chromosomes. Turpin had thought about growing cells in a lab to count chromosomes. Marthe Gautier, who had just joined their team, offered to try this. She had learned how to grow cells and stain tissues in the United States. Turpin gave her tissue samples from patients with Down syndrome. Gautier set up France's first lab for growing cells, even with very few resources.

At that time, the hospital labs didn't have a microscope that could take pictures of the slides. Gautier asked Lejeune, who worked at another research center, to help. He offered to take photos in a better-equipped lab. In August 1958, these photos showed the extra chromosome in patients with Down syndrome.

Lejeune's lab notebook shows that on 22 May 1958, he successfully found 47 chromosomes in a child with Down syndrome for the first time. This was two years after other scientists had confirmed humans have 46 chromosomes. On 13 June 1958, Lejeune found another case. He showed a picture of the chromosomes at a big science meeting in Montreal. However, the world didn't fully understand how important his discovery was until 26 January 1959. That's when the French Academy of Sciences published their first paper, showing three cases of children with Down syndrome.

In January 1959, to get ahead of similar research by English scientists, the Trousseau lab announced their findings. The paper was published with Lejeune as the first author, Gautier as the second (her name was misspelled as Gauthier), and Turpin as the last author.

On 16 March 1959, another presentation confirmed their first findings, this time with nine cases. In April 1959, an English team confirmed these results, mentioning the January 1959 paper by Lejeune, Gautier, and Turpin. The condition once called "Mongolism" became known as trisomy 21. This discovery opened up a whole new area of study in genetics, called cytogenetics, which is the study of chromosomes.

Marthe Gautier has said that Lejeune was not the only one who discovered trisomy 21. She explained in interviews and an article in 2009 that she worked alone to develop the methods needed to prepare the microscope slides. She said she was the first to notice the unusual chromosome count. According to her, Lejeune took her slides to photograph them but then presented them as his own work. Jean-Marie Le Méné, who leads the Jérôme Lejeune Foundation, says there is no proof that Gautier made the main discovery. Gautier agrees that Lejeune identified the 47th chromosome as an extra chromosome 21. However, she still says she was the first to see the abnormal number. In a letter from 1958, Lejeune thanked Gautier for "your preparations" which were key to the discovery. Gautier was also listed as a co-author on two important papers: one about the discovery of trisomy 21 and another about the cell culture methods she learned during her studies in Boston.

More Discoveries and Awards

Jérôme Lejeune continued his work in genetics. He found several other diseases caused by chromosome problems. In 1963, he identified Cri du Chat syndrome. This condition is caused by a missing piece in chromosome 5. In 1966, he described 18q-Syndrome, which happens when a part of chromosome 18 is missing. Lejeune also discovered other conditions linked to problems with chromosome 13, chromosome 9, and chromosome 8.

In 1963, Lejeune showed that missing a part of the genome (all of a person's genetic material) could also cause a recognizable disease. A few years later, American scientists came to Paris to check Lejeune's discovery. In 1962, the President of the United States personally gave him the Kennedy Prize. In 1964, the first special teaching position (chair) in human genetics was created at the Paris School of Medicine, and Lejeune was chosen for it. This was very unusual because he became a professor without taking a competitive exam.

In 1969, Lejeune received the William Allan Award. This is the highest honor in genetics, given by the American Society of Human Genetics. As of 2013, he was the only Frenchman to have won this award.

Later Life and Passing

Jérôme Lejeune was diagnosed with lung cancer in November 1993. He passed away in April 1994.

A few years later, in 1997, Pope John Paul II visited Lejeune's grave in Châlo-Saint-Mars during his trip to Paris for World Youth Day.

Veneration

The Catholic Church named Lejeune "Servant of God" when they began the process to consider him for sainthood.

On 21 January 2021, Pope Francis recognized Lejeune's heroic virtues. This led to Lejeune being declared "Venerable".

Honors and Awards

Jérôme Lejeune received many honors during his life. He was a member of important scientific groups, including:

• the French Institute’s Academy of Moral and Political Sciences
• the French Academy of Medicine
• the Pontifical Academy of Sciences
• the Lyncean Academy in Rome
• the American Academy of Arts and Sciences
• the Royal Swedish Academy
• the National Academy of Medicine in Argentina
• the University of Santiago, Chile

Lejeune also received special degrees (called honorary doctorates) from:

• University of Düsseldorf, Germany
• University of Navarra, Spain
• University of Buenos Aires, Argentina
• Pontifical Catholic University of Chile

His international roles included:

• World Health Organization (WHO)
  • Expert on human genetics (1962)
• International Commission on Radiological Protection
  • Committee member (1963)
• United Nations
  • French expert for the Scientific Committee on the Effects of Atomic Radiation

See also

In Spanish: Jérôme Lejeune para niños